Method of forming a wall from a plurality of tubes



Sept. 5, 1961 A. HUET 2,998,640

METHOD OF FORMING A WALL FROM A PLURALITY OF TUBES Filed March 4, 1957INVHVTOR. ANDRE HUET ATTORNE).

United States Patcnt Oflice Patented Sept. 5, 1961 2,998,640 METHOD OFFORMING A WALL FROM A PLURALITY OF TUBES Andre Huet, 48 Avenue duPresident Wilson, Paris, France Filed Mar. 4, 1957, Ser. No. 643,748Claims priority, application France Mar. 8, 1956 2 Claims. (Cl.291'57.4)

Several methods are known for assembling an uninterrupted wall from amultiplicity of tubes, said tubes being arranged parallel and close toone another to form panels such as are used for lining the combustionchamber of boilers.

In particular it has already been proposed to provide these tubes withprotrusions to be welded together or on to a contiguous tube having asmooth surface, that is to say having no such protrusion.

However, it is of advantage to have the tubes as close to one another aspossible so that the available area can be used to the best advantage.This close packing of the tubes is theoretically possible if these tubesare connected at the end to elbows of very small radius, provided insome case with tubulures. In actual practice these elbows with tubulureswould be used for connecting up with the header, and the tubulures onthe header could be separated from each other by the usual intervalsrequired in making a header with tubulures.

However, this involves another difiiculty since these almost contiguoustubes are difiicult to weld together along their generatrices ofcontact, since welding-especially when thin-walled tubes areconcerned-impairs the strength of the tube wall.

The known methods of assembling an uninterrupted wall from closelypacked tubes involve difiicult and costly methods of making the welds.

The purpose of the present invention is to assemble an uninterruptedwall from closely packed parallel tubes without the need for specialmethods of welding.

According to the present invention, in a known manner, one or moreridges are formed on the tube by compression of the tube, along one ormore generatrices. The profile of these symmetrical or asymmetricalridges may also have a chamfered lip. To assemble the uninterruptedpanel it is then sufiicient to weld together the chamfered lips of twoadjacent tubes, and so on.

The following description with reference to the accompanying drawings,given by way of example, explains how the invention may be embodied.

FIG. 1 shows a sectional tube having a symmetrical, chamfered ridge.

FIG. 2 is a section of a tube with an asymmetrical ridge.

FIG. 3 is a section through a tube having two symmetrical ridges at 180from each other.

FIG. 4 is a section through part of a panel assembled from tubes asshown in FIG. 3.

FIG. 5 is a section through part of a T-shaped wall.

FIG. 6 is a side elevation of the connection of the tubes to a header.

As can be seen in FIG. 1, and in accordance with the present invention,a heated tube a of circular cross-section has been subjected tocompression in dies of suitable shape along one of its generatrices, theeffect of this compression being to reduce the diameter of the tubewithout disturbing its circular cross-section, and to produce a ridge bin the zone of the heated generatrix.

To give an example; if it is desired to obtain tubes with a finaldiameter of 30 mm., and 4 mm. thick, a tube of about 40 mm. diameter iscompressed and a ridge of about 4 mm. is obtained along the generatrix,thus increasing the thickness of the wall at this point to 8 mm.

'Ilhe lip of the ridge b may be chamfered directly as seen at a, bysuitably shaping the compression die.

It is also possible, by using the same method and by making the dies ofsuitable shape, to obtain an asymmetrical profile d for the ridge of thetube e (FIG. 2).

The method of compressing the tube also makes it possible to obtainridges situated at 180 to each other, like g and h on the tube i in EIG.3. These ridges may have a triangular profile as represented.

The wall is then assembled, as shown in FIG. 4, by welding together thetwo ridges h and g of two adjacent tubes. In this case only the ridgesundergo welding so that the tube wall as such remains unaffected.

The two ridges g and h, instead of being at 180 to each other, may be atfor the angle tube in case it is desired to make an angle wall.

It is also possible to provide three or four ridges distributed roundthe periphery of the tube so as to efiect all sorts of combinations forassembling uninterrupted walls. FIG. 5 shows an angle tube k havingthree ridges l, m, n for a T-shaped wall.

The walls or panels of tubes obtained in accordance with the presentinvention have the advantage of being easily assembled and of havingtubes as closely spaced as possible which allows of using the areaavailable to the best advantage.

To assemble these tubes at their ends in the header, an elbow 0 may beprovided, as shown in Fig. 6, for joining two adjacent tubes, this elbow0 having, for instance, a tubulure p which is connected with thetubulures q on the header r. This method of assembly by means of elbowshaving tubulures allows of leaving the absolute 1y indispensableintervals on the header between the tubulures q while still producing apanel in which the tubes are as close together as possible. The spacesbetween two tubulures q and the adjacent elbows 0 may be closed by aplate s which may be Welded to the ribs t forming part of the outer areaof the elbow o.

It is, of course, understood that the details of the performance of theinvention may be modified without departing from its principle.

What I claim is:

1. A method of producing an uninterrupted Wall from a plurality ofthin-walled tubes wherein each of said tubes has at least onelongitudinal ridge extending outwardly from its exterior surfaces withthe remainder of each tube being of substantially circular cross sectionwhich comprises, compressing inwardly circular tubes to form circulartubes of smaller diameter having at least one integral longitudinalexterior ridge with a chamfered edge remote from said tube, disposingsaid tubes in axial parallel relationship by abutting the chamferededges of the ridges of the tubes, and welding each ridge to thecorresponding ridge of the next adjacent tube, whereby saiduninterrupted wall is formed without damage to the tubes.

2. A method of producing an uninterrupted wall from a plurality ofthin-walled tubes wherein said tubes are formed with two substantiallydiametrically opposite longitudinal ridges extending outwardly fromtheir exterior surfaces with the remainder of the tubes being ofsubstantially circular cross section which comprises, compressinginwardly circular tubes to form circular tubes of smaller diameterhaving two diametrically opposite exterior integral longitudinal ridgeseach formed with a chamfered edge remote from said tube, disposing saidtubes in axial parallel relationship by abutting the chamfered edges ofthe ridges of the tubes, and welding each ridge to the correspondingridge of said next ad- Stockstill Apr. 22, 1952 Chapman Nov. 24, 1953Beck Feb. 14, 1956 FOREIGN PATENTS Great Britain 1892

